scholarly journals The Influence of Solid-State Drawing on Mechanical Properties and Hydrolytic Degradation of Melt-Spun Poly(Lactic Acid) (PLA) Tapes

Fibers ◽  
2015 ◽  
Vol 3 (4) ◽  
pp. 523-538 ◽  
Author(s):  
Fang Mai ◽  
Wei Tu ◽  
Emiliano Bilotti ◽  
Ton Peijs
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Solid State ◽  
Hydrolytic Degradation ◽  
Poly Lactic Acid ◽  
Melt Spun

scholarly journals Properties of Poly(Lactic Acid) Filled with Hydrophobic Cellulose/SiO2 Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Kittithorn Lertphirun ◽  
Kawee Srikulkit
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Hydrolytic Degradation ◽  
Poly Lactic Acid ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Twin Screw ◽  
Hydrolysis Of Cellulose ◽  
One Step ◽  
Hydrolysis Of

Hydrophobic cellulose/SiO2 composites were prepared. Resultant hydrophobic cellulose/SiO2 composites were melt mixed with PLA using a twin-screw extruder to obtain 10 wt% masterbatch. Again, 10 wt% masterbatch was melt mixed with virgin PLA, resulting in PLA containing hydrophobic cellulose/SiO2 at various contents (1 wt%, 3 wt%, and 5 wt%) using a twin-screw extruder (barrel zone temperature: 150/160/170/180/190°C (die zone)). Injection-molded samples were prepared for mechanical properties evaluation. Results showed that poor mechanical properties found at low percent loadings were associated with a significant depolymerization of masterbatch composition due to twice thermal treatments. Note that 10 wt% masterbatch was subjected to injection molding straight away in a one-step process. Results showed that 10 wt% hydrophobic cellulose/SiO2/PLA composites exhibited mechanical properties equivalent to neat PLA. Importantly, the addition of hydrophobic cellulose/SiO2 at high percent loading could favor landfill degradation of PLA via water absorption ability of cellulose. It was expected that enzymatic hydrolysis of cellulose resulted in the formation of lactic acid and silicic acid which consequently catalyzed the hydrolytic degradation (acid hydrolysis) of PLA. The hydrolytic degradation produced carboxylic acid end group which further accelerated the degradation rate.

Preparation and characterization of chitosan grafted poly(lactic acid) films for biomedical composites

2020 ◽  
Vol 40 (4) ◽  
pp. 333-341
Author(s):  
Tonmoy Debnath ◽  
Md. Sazedul Islam ◽  
Sirajul Hoque ◽  
Papia Haque ◽  
Mohammed Mizanur Rahman
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Polymer Composites ◽  
Average Molecular Weight ◽  
Krebs Cycle ◽  
Hydrolytic Degradation ◽  
Film Surface ◽  
Poly Lactic Acid ◽  
Aqueous Environment ◽  
Weight Retention

AbstractPolymer composites offer a great advantage in biomedical field over the traditional materials used like, metal, ceramics, or polymer alone. Polymer composites provide tailor-made facilities to design required physiological and mechanical properties in biomedical products. Poly(lactic acid) (PLA) is a popular aliphatic polyester used in various biomedical products because they have a renewable source and after resorption they enter well into the Krebs cycle of the human body. However, PLA suffers from hydrolysis and subsequent weight loss in aqueous environment. To improve the hydrolytic properties of hydrophobic PLA and to incorporate the biocompatibility from chitosan (CS) into it, in this study CS has been grafted onto PLA film. CS with 78% of degree of deacetylation and viscosity average molecular weight of about 8,31,760 Da was grafted onto hydrolyzed PLA film surface. Kjeldahl analysis confirmed the attachment of CS onto the PLA films. From thermal stability analysis, it was observed that percentage of weight retention at 600°C of the CS-g-PLA was around 15% higher than that of pure PLA. The mechanical properties of final CS-grafted-PLA composites showed more resistance to hydrolytic degradation than that of pure PLA film.

scholarly journals Water-Induced Breaking of Interfacial Cohesiveness in a Poly(lactic acid)/Miscanthus Fibers Biocomposite

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2285
Author(s):  
Nicolas Delpouve ◽  
Hajar Faraj ◽  
Clément Demarest ◽  
Eric Dontzoff ◽  
Marie-Rose Garda ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Hydrolytic Degradation ◽  
Thermomechanical Properties ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Incomplete Filling ◽  
The Matrix ◽  
High Elongation ◽  
The Impact

The impact of the immersion in water on the morphology and the thermomechanical properties of a biocomposite made of a matrix of poly (lactic acid) (PLA) modified with an ethylene acrylate toughening agent, and reinforced with miscanthus fibers, has been investigated. Whereas no evidence of hydrolytic degradation has been found, the mechanical properties of the biocomposite have been weakened by the immersion. Scanning electron microscopy (SEM) pictures reveal that the water-induced degradation is mainly driven by the cracking of the fiber/matrix interface, suggesting that the cohesiveness is a preponderant factor to consider for the control of the biocomposite decomposition in aqueous environments. Interestingly, it is observed that the loss of mechanical properties is aggravated when the stereoregularity of PLA is the highest, and when increasing the degree of crystallinity. To investigate the influence of the annealing on the matrix behavior, crystallization at various temperatures has been performed on tensile bars of PLA made by additive manufacturing with an incomplete filling to enhance the contact area between water and polymer. While a clear fragilization occurs in the material crystallized at high temperature, PLA crystallized at low temperature better maintains its properties and even shows high elongation at break likely due to the low size of the spherulites in these annealing conditions. These results show that the tailoring of the mesoscale organization in biopolymers and biocomposites can help control their property evolution and possibly their degradation in water.

Higher-order structures and mechanical properties of stereocomplex-type poly(lactic acid) melt spun fibers

Polymer ◽  
2006 ◽  
Vol 47 (16) ◽  
pp. 5965-5972 ◽  
Author(s):  
Yukiko Furuhashi ◽  
Yoshiharu Kimura ◽  
Naoko Yoshie ◽  
Hideki Yamane
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Higher Order ◽  
Poly Lactic Acid ◽  
Melt Spun ◽  
Order Structures ◽  
Spun Fibers

Conductivity and mechanical properties of carbon black-reinforced poly(lactic acid) (PLA/CB) composites

2021 ◽  
Author(s):  
Jipeng Guo ◽  
Chi-Hui Tsou ◽  
Yongqi Yu ◽  
Chin-San Wu ◽  
Xuemei Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Carbon Black ◽  
Poly Lactic Acid

scholarly journals A Review: Research Progress in Modification of Poly (Lactic Acid) by Lignin and Cellulose

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 776
Author(s):  
Sixiang Zhai ◽  
Qingying Liu ◽  
Yuelong Zhao ◽  
Hui Sun ◽  
Biao Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Composite Materials ◽  
Crystallization Rate ◽  
Research Progress ◽  
Poly Lactic Acid ◽  
Green Composite ◽  
Materials Development ◽  
Research Attention ◽  
Biomass Components

With the depletion of petroleum energy, the possibility of prices of petroleum-based materials increasing, and increased environmental awareness, biodegradable materials as a kind of green alternative have attracted more and more research attention. In this context, poly (lactic acid) has shown a unique combination of properties such as nontoxicity, biodegradability, biocompatibility, and good workability. However, examples of its known drawbacks include poor tensile strength, low elongation at break, poor thermal properties, and low crystallization rate. Lignocellulosic materials such as lignin and cellulose have excellent biodegradability and mechanical properties. Compounding such biomass components with poly (lactic acid) is expected to prepare green composite materials with improved properties of poly (lactic acid). This paper is aimed at summarizing the research progress of modification of poly (lactic acid) with lignin and cellulose made in in recent years, with emphasis on effects of lignin and cellulose on mechanical properties, thermal stability and crystallinity on poly (lactic acid) composite materials. Development of poly (lactic acid) composite materials in this respect is forecasted.

scholarly journals Mechanical Properties and Bioactivity of Poly(Lactic Acid) Composites Containing Poly(Glycolic Acid) Fiber and Hydroxyapatite Particles

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 249
Author(s):  
Han-Seung Ko ◽  
Sangwoon Lee ◽  
Doyoung Lee ◽  
Jae Young Jho
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Flexural Strength ◽  
Interfacial Adhesion ◽  
Glycolic Acid ◽  
Compact Bone ◽  
Poly Lactic Acid ◽  
Coupling Reactions ◽  
The Poor ◽  
Human Compact Bone

To enhance the mechanical strength and bioactivity of poly(lactic acid) (PLA) to the level that can be used as a material for spinal implants, poly(glycolic acid) (PGA) fibers and hydroxyapatite (HA) were introduced as fillers to PLA composites. To improve the poor interface between HA and PLA, HA was grafted by PLA to form HA-g-PLA through coupling reactions, and mixed with PLA. The size of the HA particles in the PLA matrix was observed to be reduced from several micrometers to sub-micrometer by grafting PLA onto HA. The tensile and flexural strength of PLA/HA-g-PLA composites were increased compared with those of PLA/HA, apparently due to the better dispersion of HA and stronger interfacial adhesion between the HA and PLA matrix. We also examined the effects of the length and frequency of grafted PLA chains on the tensile strength of the composites. By the addition of unidirectionally aligned PGA fibers, the flexural strength of the composites was greatly improved to a level comparable with human compact bone. In the bioactivity tests, the growth of apatite on the surface was fastest and most uniform in the PLA/PGA fiber/HA-g-PLA composite.

scholarly journals Poly(Lactic Acid)–Poly(Butylene Succinate)–Sugar Beet Pulp Composites; Part I: Mechanics of Composites with Fine and Coarse Sugar Beet Pulp Particles

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2531
Author(s):  
Rodion Kopitzky
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Sugar Beet ◽  
Cell Structure ◽  
Sugar Beet Pulp ◽  
Poly Lactic Acid ◽  
Butylene Succinate ◽  
Fracture Patterns ◽  
Beet Pulp ◽  
The Impact

Sugar beet pulp (SBP) is a residue available in large quantities from the sugar industry, and can serve as a cost-effective bio-based and biodegradable filler for fully bio-based compounds based on bio-based polyesters. The heterogeneous cell structure of sugar beet suggests that the processing of SBP can affect the properties of the composite. An “Ultra-Rotor” type air turbulence mill was used to produce SBP particles of different sizes. These particles were processed in a twin-screw extruder with poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) and fillers to granules for possible marketable formulations. Different screw designs, compatibilizers and the use of glycerol as a thermoplasticization agent for SBP were also tested. The spherical, cubic, or ellipsoidal-like shaped particles of SBP are not suitable for usage as a fiber-like reinforcement. In addition, the fineness of ground SBP affects the mechanical properties because (i) a high proportion of polar surfaces leads to poor compatibility, and (ii) due to the inner structure of the particulate matter, the strength of the composite is limited to the cohesive strength of compressed sugar-cell compartments of the SBP. The compatibilization of the polymer–matrix–particle interface can be achieved by using compatibilizers of different types. Scanning electron microscopy (SEM) fracture patterns show that the compatibilization can lead to both well-bonded particles and cohesive fracture patterns in the matrix. Nevertheless, the mechanical properties are limited by the impact and elongation behavior. Therefore, the applications of SBP-based composites must be well considered.

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